The maritime world is filled with specialist vocabulary the conventional spelling of which is not always obvious. Boatswain/bosun and forecastle/focsle are among the best-known examples of words that have two accepted spellings, one etymologically correct, the other based on pronunciation. Another source of uncertainty is whether a term is one word or two, or hyphenated, as in sea anchor, seabag, sea bass, seabed, sea-lane.
This list is my attempt to impose a bit of order on the subject. It is by no means immutable, and I welcome suggestions, corrections, and discussion about the choices reflected here.
A: Alpha
admiral (rear a.; vice a., etc.)
Admiralty, the
admiralty law
admiral of the fleet
aftercastle
aircraft carrier
amphora (pl. amphorae)
archrival
art deco
art nouveau
Atlantic ferry
B: Bravo
bareboat
battlecruiser
battle fleet
battle line
battleship
bayman
bayside
beachcomber
beachfront
beachgoer
beach grass
beachhead
beachside
Bermuda rig
bilge keel
bilgewater
Blackwall hitch
blockade-runner
blue water (n.)
blue-water (adj.)
boatbuilder/-ing
boat hook
boathouse
boatload
boatman
boatneck
boat people
boat shoe
boat shop
boatswain (= bosun)
boat train
boatyard
boltrope
bomb-ship, -ketch, etc.
bosun (= boatswain)
bowline
box ship; box boat (container ship)
break-bulk freighter
breakwater
build-up (n.)
built-up (adj.)
bumboat
buntline
bycatch
C: Charlie
cable-laid rope
cable length
canal boat
capital ship
carrick bend
carvel-built
carvel construction
cat-o’-nine-tails
cat’s-paw (knot)
centerboard
centerline
chain pump
charter party
-class: King George V-class (e.g.)
clinker-built
clinker (or lapstrake) construction
close-hauled
clove hitch
coastwise
commerce raider
compound engine
Coriolis effect/force
counterclockwise
countercurrent
court-martial; pl. courts-martial (n. & v.)
crash-land
crisscrossing
cross-braced
crow’s nest
cruise ship
D: Delta
day-tripper
deadrise
deadweight tonnnage
deck chair
deckhand
deckhouse
deep-sea
deep-water
depth charge (n.)
depth-charge (v.)
depth sounder
displacement tonnage
dive-bomber
dockhand
dockland
dockmaster
dockside
dockworker
dockyard
downrange
downriver
downstream
downtime
downwind
dry-dock (v.)
dry dock (n.)
dugout
E: Echo
ebb tide
en echelon [roman]
equator, the
escort carrier
F: Foxtrot
ferryboat
ferryman
figure eight
fireship
fisherman’s bend
fishing boat
flight deck
floatplane
floodgate
floodplain
flood stage
flood tide
floodwater
floodway
flying jib
focsle (forecastle)
fore and aft (adv.)
fore-and-aft (adj.)
fore-and-after
forecastle (focsle)
foredeck
forefoot
fore gaff-topsail
foreland
foremast
forepeak
forereach
foresail
foresheet
foreshore
forestay
forestaysail
foretop
foretopman
fore-topmast
frame-first construction
freeboard
freshwater (n., adj.)
full speed
full-rigged ship
G: Golf
gaff rig (n.); gaff-rigged (adj.)
gaff-topsail
gale force winds
gangplank
gangway
granny knot
gappling chain, ~hook
grapeshot
great galley
gunboat
gunboat diplomacy
gun-deck
gun-founder, gun-foundry
gun-port
gunpoint
gunpowder
gun room
gunrunning, -er
gunship
H: Hotel
half hitch
handrail
hand(i)work
harbormaster
harbor seal
harborside
Harbor (as in Boston, or any named)
hawsehole
hawser-laid rope
headland
headroom
headsail
headwater
headway
headwind
helm-deck
helmsman
high tide
high water
high-water mark
holdfast
home port (n.)
homeport (v.)
horsepower (indicated horsepower, etc.)
hosepipe
hurricane force winds
I: India
ice age
ice ax
iceberg
iceblink
iceboat
icebound
ice cap
ice-cold (adj.)
icefall
ice field
ice floe
ice fog
icehouse
iceman
ice-out
ice pick
ice sheet
ice storm
ironclad
J: Juliett
jolly boat
jury rig (n.)
jury-rig (v.)
jury-rigged (adj.)
K: Kilo
keelboat
keelhaul
keel-rope
keelson
L: Lima
laborsaving
land breeze
landing craft
landmark
land mass
landward
lapstrake construction
lateen sail
lay-up (n.)
layover
leeboard
lee gauge
lee shore
leeward
leeway
Liberty ship
lightship
line-ahead (adj.)
line-abreast (adj.)
line of battle
line officer
line of sight
line squall
load line (n.)
load-line (adj.)
logboat
long-range
longship
longshoreman
loose-footed
low water
low-water mark
lubber line
lubber’s hole
lugsail
M: Mike
made mast
main deck
main gaff-topsail
mainland
mainmast
mainsail
mainsheet
mainstay
maintop
main-topmast
main yard
man-of-war
manrope
mapmaker, ~ing
masthead
mast-step
merchant cruiser
merchant shp
merchantman
midatlantic
mine-laying
minelayer
mizzenmast
mizzen sail
Morse code
mortise-and-tenon (adj.)
motor schooner
motorship
moveable
N: November
navaid
Navy Cross
navy yard
near-sister (adj.)
neoclassical
Northeast Passage
Northwest Passage
O: Oscar
oarlock
oceanfront
oceangoing
ocean liner
oceanside
off course
offload(~ing)
offshore (adj., adv., prep.)
orlop deck
outrigger
overhand knot
P: Papa
paddleboat
paddle steamer
paddle wheel(~er)
phytoplankton
pilot cutter
point-blank (adj./adv.)
pole mast
poop deck
porthole
port of call
port of entry
port of trade
prisoner of war
promenade deck
propeller
PT-boat
purpose-built (adj.)
Q: Quebec
quadruple-expansion engine
quarter rudder
R: Romeo
radio beacon
retour ship
right(s)-of-way
riverbank
riverbed
riverboat
river-craft
riverfront
river plain
riverside
riverward
rolling hitch
round ship
round-trip
roustabout
rowboat
rowing boat
rowing machine
rowlock
rudderpost
running light
running rigging
S: Sierra
sailboard
sailboat
sailcloth
sailmaker
sailing school
sailing school vessel
sail training
sail training ship
Saint Elmo’s fire
saltwater (n., adj.)
schoolship
sea anchor
seabag
sea bass
seabed
Seebee
seabird
sea biscuit
seaboard
seaborne
sea breeze
sea buoy
sea captain
sea change
sea chest
seacoast
seacraft
sea cucumber (sea slug)
sea dog
sea duty
Sea Explorer
seafarer/~ing
sea fire
seafloor
seafood
seafront
seagirt
seagoing
sea green
seagull
sea king
sea-lane
sea lawyer
sea legs
sea level
sealift
sea lion
sealskin
sea-maid
seaman
seamanlike
seamanship
seamark
sea mile
seamount
seaplane
seaport
sea power
seaquake
sea room
sea rover
sea route
sea scallop
seascape
sea serpent
seashell
seashore
sea serpent
seasick
seaside
sea slug (sea cucumber)
sea snake
sea stores
seatrain
sea trout
sea turtle
sea urchin
seawall
seaward(s)
seawater
seaway
seaweed
seaworthy
sea wrack
shallow-draft (adj.)
shear-hook
sheepshank
sheerstrake
sheet bend
shell-first construction
ship biscuit
shipboard
shipborne
ship breaker
shipbuilder/~ing
shipfitter
shiphandling
shiplap
shipload
shipman
shipmaster
shipmate
ship of state
ship of the line
shipowner, -ing
shipping lane
shipshape
ship’s papers
ship timber
ship time
shipway
shipworm
shipwreck (n., v.)
shipwright
shipyard
shoal-draft (adj.)
shoal water
shorebird
shorefront
shore leave
shore patrol
shoreside (adj.)
shroud-laid rope
sick bay
side-wheel(~er)
single-handed (adj./adv.)
single-hander
sister-ship
skin boat
slave owner
slave ship
slipknot
sloop of war
snagboat
spar torpedo
spritsail
squall line
square rig
square-rigged (before noun)
square-rigger
square knot
square sail
standing rigging
staysail
steamboat
steamboat Gothic
steam boiler
steam chest
steam engine
steamer rug
steamer trunk
steamfitter
steamship
steam turbine
steering oar
stempost
sterncastle
stern chase (n.)
stern chaser
sternpost
stern sheets
sternward
sternway
stern-wheel(~er)
stevedore knot
streambed
streamside
sundeck
surgeon’s knot
T: Tango
tabernacle mast
tall ship
thole pin
tideland
tidemark
tide pool
tidewater
timber hitch
tonnage: gross register tonnage, etc.
topcastle
topgallant
topgallant mast
top-hamper
top-heavy
topmast
topsail
torpedo boat
torpedo-boat destroyer
torpedo bomber
torpedo tube
trade route
trade wind
training ship
transatlantic
transoceanic
transpacific
transship
treenail
triple-expansion engine
turboelectric
Turk’s head
tween deck
U: Uniform
ultra large crude carrier (ULCC)
UN (adj.)
undertow
underwater
under way (adv.)
underway (adj.)
upriver
upstream
U.S. (adj.)
V: Victor
very large crude carrier (VLCC)
V-bottom hull
Victory ship
W: Whiskey
waterborne
watercourse
watercraft
waterfront
water gate
water gauge
water level
waterline
waterlog
waterman
watermark
waterpower
water privilege
waterproof
water rat
water-repellent
water-resistant
water right
waterscape
watershed
waterside
water ski (n.)
water-ski (v.)
water-skier
waterspout
water taxi
watertight
waterway
waterwheel
water wings
waterworks
waterworn
waybill
waypoint
way station
weather gauge
weather-leech
Western Europe (post-WW2)
whale catcher
whaleback
whaleboat
whalebone
whale shark
whaleship
wharf boat
wharfmaster
windage
windblown
wind-borne
Windbreaker (™)
windchill
windjammer
windlass
windproof
windscreen
windshield
wind tunnel
windward
wing and wing (adv.)
wolf pack
X: Xray
xebec
Y: Yankee
yacht club
yachtsman
yardarm
yardarm-to-yardarm
year-round
Z: Zulu
zebra mussel
zero-emission
zero hour
zooplankton
Zuider Zee
This has every Naval term I could ever hope for!